Network Generator v3.00 Tutorial 1.

THE NETWORK GENERATOR TUTORIAL

1. How to generate automatically an extended CNO network, on a given temperature grid. 1a. First step: go to the Automatic Generation section and select

the Zmin, Zmax boundary of the network (here Zmin=6, Zmax=9)
the type of reactions (here proton-captures)
the isotopic boundary of the network (here one isotope beyond the stability valley)

Note: If this is not the first time Netgen is run from your current IP address, it might be necessary to click first on `Clear network'; otherwise, the selected reactions will be appended to the network generated by the previous Netgen run.

Then click on button 'Generate network' and proceed to step 1b below.

Here is a screen copy of the form corresponding to step 1a.

I. Automatic generation of network:

(The default values generate the CNO-cycle network)

Zmin (1 - 93): Zmax (1 - 93):

Reactions to be included:

(p,gamma)

(p,n) (p,alpha)

(n,gamma)

(n,p) (n,alpha)

(alpha,gamma)

(alpha,p) (alpha,n)

(gamma,p) (gamma,n) (gamma,alpha)

Define the left and right borders of the network

Left Right

Proton drip line

Proton-rich stability boundary

Neutron-rich stability boundary

Neutron drip line

Mass offset

The mass offset field defines the offset (either positive or negative) to be added to the atomic mass of the selected boundary (i.e., drip lines or boundaries of stability valley).

1b. Second step: Provide the temperature grid. The network constructed so far appears at the end of the form. It is still possible to add reactions at this step by clicking on Back to network construction.
Click on Compute rates to start the computation of the reaction rates (At this stage, duplicate reactions are removed, and the network is re-ordered in alphabetical order of the first species!). Since this process may take a while, it is possible to provide an e-mail address to be informed when the rates are ready.

It is not yet possible to edit the network at this stage, e.g. by removing some reactions. This will be possible in a future release of Netgen.

Results are described in step 1c.

Here is a screen copy of the form corresponding to step 1b.

Request from: astrohp5.ulb.ac.be (164.15.125.42) Please send comments and suggestions to ajorisse%astro.ulb.ac.be List the current network

Current network is:

bib_code Reaction
1        1 C  11 ( 1 PROT , 0 OOOOO)  1 N  12 
1        1 C  11 ( 1 PROT , 1 HE  4)  1 B   8 
1        1 C  11 ( 0 OOOOO, 0 OOOOO)  1 B  11 
1        1 C  12 ( 1 PROT , 0 OOOOO)  1 N  13 
1        1 C  12 ( 1 PROT , 1 NEUT )  1 N  12 
1        1 C  12 ( 1 PROT , 1 HE  4)  1 B   9 
1        1 C  13 ( 1 PROT , 0 OOOOO)  1 N  14 
.........................

1        1 F  20 ( 1 PROT , 0 OOOOO)  1 NE 21 
1        1 F  20 ( 1 PROT , 1 NEUT )  1 NE 20 
1        1 F  20 ( 1 PROT , 1 HE  4)  1 O  17 
1        1 F  20 ( 0 OOOOO, 0 OOOOO)  1 NE 20

1c. Results: Reaction rates: Three files have been created at the end of the process, and are available at http://www-astro.ulb.ac.be/tmp.
They contain:

the network
the table with the reaction rates
the log file listing the bibliographical references of all the rates available for the reactions included in the considered network, and the rate provided in the table. Possible problems in finding or computing the rate are also reported in this file.

The files are named, respectively:

tmpIP_address.tail
tmpIP_address.rates
tmpIP_address.refs

where IP_address is the IP address of the client, as indicated here. Example: tmp164.15.125.42.rates

What is to be found in the table of reaction rates?

This table provides the number of reactions per sec per (cm³mole^-1)^(N-1), where N refers to the number of particles in the entrance channel:

Multi-particle reactions: Maxwellian-average N_Av^(N-1) < sigma v> [(cm³mole^-1)^(N-1) s^-1]

Radiative neutron capture reactions: Maxwellian-average N_Av < sigma v > [cm³mole^-1 s^-1]

N_Av < sigma v >

is generally derived from the Maxwellian-averaged cross section <sigma v>/v_T using the formula

N_Av < sigma v > = 2.645 10⁴ (kT)^(1/2) <sigma v>/v_T

, with N_Av < sigma v > expressed in cgs units, kT in keV and <sigma v>/v_T in mb

Beta-decays, electron captures, or photodesintegrations: decays per s [lambda (s^-1)]

Some beta-decay rates from Takahashi & Yokoi (1987) consist of four successive columns, corresponding to electronic number densities of 1, 3, 10 and 30 x 10²⁶ cm^-3 A special treatment applies to electron captures by 7Be, as indicated in the corresponding log file

The reaction kind is coded in the header line labelled Type in the following way:

--: two-particle reactions
---: three-particle reactions
----: four-particle reactions
+: photodissociation or beta-decay
++: electron capture
+++: electron capture on Be7
nE+mm: value of the electron number density (in units of electrons/cm³) for beta-decay rates dependent upon electron number density

NaN (`Not a Number`) symbols are given in the table for temperatures at which no data are available
Reverse reaction rates with no data available for the direct reaction are set to NaN or to .1000E-98,
although the exact value may possibly be much larger than .1000E-98 (especially for neutron-capture reactions)!

The energetics (Q = Qrad + Qnu) of the reaction is also provided in the header.
Q is computed from Audi & Wapstra mass table (Audi G., Wapstra A.H., 1995, Nucl. Phys. A595, 409) or Goriely et al. mass table (Goriely S., Pearson J.M., Tondeur F., 2000, Atomic Data Nucl. Data Tables, in press), as the difference between the mass excess in the entrance and exit chanels.
Qrad provides the radiative losses, i.e., Q - Qnu, where Qnu is the energy possibly carried away by neutrinos.
The neutrino loss Qnu is computed according to Eqs. 1 and 2 of Fowler W.A., Caughlan G.R. & Zimmerman B.A. (1975, ARA&A 13, 69).

A fortran routine is available to read the table of reaction rates.

Here is an example of reaction rates from Netgen:

#             1 C  11    1 C  11    1 C  11    1 C  12    1 C  12    1 C  12    1 C  13    1 C  13    1 C  13    1 C  14    
#                 +          +          +          +          +          +          +          +          +          +      
#              1 PROT     1 PROT     0 OOOOO    1 PROT     1 PROT     1 PROT     1 PROT     1 PROT     1 PROT     1 PROT    
#                 =          =          =          =          =          =          =          =          =          =      
#              0 OOOOO    1 HE  4    0 OOOOO    0 OOOOO    1 NEUT     1 HE  4    0 OOOOO    1 NEUT     1 HE  4    0 OOOOO   
#                 +          +          +          +          +          +          +          +          +          +      
#             1 N  12    1 B   8    1 B  11    1 N  13    1 N  12    1 B   9    1 N  14    1 N  13    1 B  10    1 N  15    
#
# Qrad(MeV)       .602     -7.406      1.401      1.944    -18.120     -7.552      7.551     -3.002     -4.062     10.208    
# Qnu (MeV)       .000       .000       .582       .000       .000       .000       .000       .000       .000       .000    
# Type              --         --          +         --         --         --         --         --         --         --    
#
#       T8
#
      .5000  .1826E-08  .1000E-98  .5663E-03  .1400E-07  .1000E-98  .1000E-98  .5530E-07  .1000E-24  .1000E-98  .5689E-07  
     1.0000  .2415E-05  .1000E-98  .5663E-03  .2180E-04  .1000E-98  .1000E-98  .8430E-04  .1000E-24  .1000E-98  .7857E-04  
     1.5000  .7791E-04  .1000E-98  .5663E-03  .8080E-03  .1000E-98  .1000E-98  .3000E-02  .1000E-24  .1000E-98  .2551E-02  
     2.0000  .7042E-03  .1000E-98  .5663E-03  .8660E-02  .1000E-98  .1000E-98  .2930E-01  .1000E-24  .1000E-98  .2332E-01  
     2.5000  .3457E-02  .1000E-98  .5663E-03  .5500E-01  .1000E-98  .1000E-98  .1540E+00  .1000E-24  .1134E-86  .1233E+00  
     3.0000  .1205E-01  .1000E-98  .5663E-03  .2780E+00  .1000E-98  .1000E-98  .5810E+00  .1000E-24  .5679E-72  .4930E+00  
     3.5000  .3377E-01  .1000E-98  .5663E-03  .1150E+01  .1000E-98  .1000E-98  .1960E+01  .1000E-24  .1141E-62  .1594E+01  
     4.0000  .8116E-01  .1816E-94  .5663E-03  .3810E+01  .1000E-98  .8882E-95  .6040E+01  .1000E-24  .2293E-53  .4289E+01  
     4.5000  .1739E+00  .1636E-83  .5663E-03  .1020E+02  .1000E-98  .1026E-84  .1690E+02  .1000E-24  .1063E-47  .9916E+01  
     5.0000  .3407E+00  .1007E-74  .5663E-03  .2280E+02  .1000E-98  .1184E-74  .4200E+02  .6390E-22  .4930E-42  .2030E+02  
#
#             1 C  14    1 C  14    1 C  15    1 C  15    1 C  15    1 C  15    1 N  13    1 N  13    1 N  13    1 N  13    
#                 +          +          +          +          +          +          +          +          +          +      
#              1 PROT     1 PROT     1 PROT     1 PROT     1 PROT     0 OOOOO    1 PROT     1 PROT     1 PROT     0 OOOOO   
 #                 =          =          =          =          =          =          =          =          =          =      
#              1 NEUT     1 HE  4    0 OOOOO    1 NEUT     1 HE  4    0 OOOOO    0 OOOOO    1 NEUT     1 HE  4    0 OOOOO   
#                 +          +          +          +          +          +          +          +          +          +      
#             1 N  14    1 B  11    1 N  16    1 N  15    1 B  12    1 N  15    1 O  14    1 O  13    1 C  10    1 C  13    
#
# Qrad(MeV)      -.625      -.784     11.479      8.990      1.368      4.708      4.628    -18.548     -5.490      1.508    
# Qnu (MeV)       .000       .000       .000       .000       .000      5.064       .000       .000       .000       .712    
# Type              --         --         --         --         --          +         --         --         --          +    
#
#       T8
#
      .5000  .7413E-57  .4429E-98  .1000E-98  .1000E-98  .1000E-98  .2830E+00  .4620E-09  .1000E-98  .1000E-98  .1160E-02  
......................................

What is to be found in the log file?

The log file lists all bibliographical references available for the requested reactions (along with the date of inclusion of the library), and the reference selected for the given reaction.

Here is an example of log file:

     1   1 C  11 ( 1 PROT , 0 OOOOO)  1 N  12 

 Number of rates available = 3

 #  Date    Reference 
 1       0  WARNING: Not valid above T9 = 1!! Descouvemont P., Baraffe I
            ., 1990, Nucl.Phys. A514, 66                                
 2       0  Wiescher M., Goerres J., Graff S., Buchmann L., Thielemann F
            .K., 1989, ApJ 343, 352                                     
 3       0  CF88                                                        

 Ref. # 1 selected for reaction 1 C  11 ( 1 PROT , 0 OOOOO)  1 N  12 
===============================================================================
     2   1 C  11 ( 1 PROT , 1 HE  4)  1 B   8 

 Data for computing inverse factor for B(b,a)A:
  Q(MeV) A(B) spin(B) A(b) g(b) Kronecker(B,b)  stoe(B) stoe(b)
 -7.4060  11     1.5  1.0  2.0     .0            1       1
           8     2.0  4.0  1.0     .0            1       1
         A(A) spin(A) A(a) g(a) Kronecker(A,a)  stoe(A) stoe(a)

 Number of rates available = 1

 #  Date    Reference 
 1  240493  WARNING: Valid T9 < 0.8! Descouvemont P., Baraffe I., 1990, 
             Nucl. Phys. A514, 66                                       

 Ref. # 1 selected for reaction 1 B   8 ( 1 HE  4, 1 PROT )  1 C  11 
===============================================================================
     3   1 C  11 ( 0 OOOOO, 0 OOOOO)  1 B  11

........................................................
===============================================================================

Here is an example of network file. The first column is the bibliographic index as given in the log file:

1        1 C  11 ( 1 PROT , 0 OOOOO)  1 N  12 
1        1 C  11 ( 1 PROT , 1 HE  4)  1 B   8 
1        1 C  11 ( 0 OOOOO, 0 OOOOO)  1 B  11 
1        1 C  12 ( 1 PROT , 0 OOOOO)  1 N  13 
1        1 C  12 ( 1 PROT , 1 NEUT )  1 N  12 
1        1 C  12 ( 1 PROT , 1 HE  4)  1 B   9 
1        1 C  13 ( 1 PROT , 0 OOOOO)  1 N  14 
.........................

1        1 F  20 ( 1 PROT , 0 OOOOO)  1 NE 21 
1        1 F  20 ( 1 PROT , 1 NEUT )  1 NE 20 
1        1 F  20 ( 1 PROT , 1 HE  4)  1 O  17 
1        1 F  20 ( 0 OOOOO, 0 OOOOO)  1 NE 20

	(p,gamma)
	(p,n) (p,alpha)
	(n,gamma)
	(n,p) (n,alpha)
	(alpha,gamma)
	(alpha,p) (alpha,n)
	(gamma,p) (gamma,n) (gamma,alpha)

	Left	Right
Proton drip line
Proton-rich stability boundary
Neutron-rich stability boundary
Neutron drip line
Mass offset

THE NETWORK GENERATOR TUTORIAL

I. Automatic generation of network:

Reactions to be included:

Define the left and right borders of the network

The Network Generator